The rise of social networking, and the involvement of advertisers in these channels, was one of 2010’s mega-stories—not least in the UK. Though spending in social networks is still a fraction of total online ad spending, many UK brands have leapt at the chance to engage with consumers in an environment where they spend increasing amounts of time and are highly motivated to share their thoughts. eMarketer estimates social network ad spending in the UK will rise from £130 million ($203 million) this year to £275 million ($430 million) by 2012, an increase of more than 110% in two years. This will boost social network ad spending from 3% of all online ad spending to 6% over the same time period.
via UK Social Network Ad Spending to Double by 2012 – eMarketer.